From 2a3d15f270efa50d78d8a32d895e9d5396668f3a Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 6 Apr 2021 16:40:26 -0300
Subject: vfio/mdev: Add missing typesafety around mdev_device

The mdev API should accept and pass a 'struct mdev_device *' in all
places, not pass a 'struct device *' and cast it internally with
to_mdev_device(). Particularly in its struct mdev_driver functions, the
whole point of a bus's struct device_driver wrapper is to provide type
safety compared to the default struct device_driver.

Further, the driver core standard is for bus drivers to expose their
device structure in their public headers that can be used with
container_of() inlines and '&foo->dev' to go between the class levels, and
'&foo->dev' to be used with dev_err/etc driver core helper functions. Move
'struct mdev_device' to mdev.h

Once done this allows moving some one instruction exported functions to
static inlines, which in turns allows removing one of the two grotesque
symbol_get()'s related to mdev in the core code.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <3-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 include/linux/mdev.h | 58 +++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 12 deletions(-)

(limited to 'include/linux/mdev.h')

diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 27eb383cb95d..52f7ea19dd0f 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -10,7 +10,21 @@
 #ifndef MDEV_H
 #define MDEV_H
 
-struct mdev_device;
+struct mdev_device {
+	struct device dev;
+	struct mdev_parent *parent;
+	guid_t uuid;
+	void *driver_data;
+	struct list_head next;
+	struct kobject *type_kobj;
+	struct device *iommu_device;
+	bool active;
+};
+
+static inline struct mdev_device *to_mdev_device(struct device *dev)
+{
+	return container_of(dev, struct mdev_device, dev);
+}
 
 /*
  * Called by the parent device driver to set the device which represents
@@ -19,12 +33,17 @@ struct mdev_device;
  *
  * @dev: the mediated device that iommu will isolate.
  * @iommu_device: a pci device which represents the iommu for @dev.
- *
- * Return 0 for success, otherwise negative error value.
  */
-int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
+static inline void mdev_set_iommu_device(struct mdev_device *mdev,
+					 struct device *iommu_device)
+{
+	mdev->iommu_device = iommu_device;
+}
 
-struct device *mdev_get_iommu_device(struct device *dev);
+static inline struct device *mdev_get_iommu_device(struct mdev_device *mdev)
+{
+	return mdev->iommu_device;
+}
 
 /**
  * struct mdev_parent_ops - Structure to be registered for each parent device to
@@ -126,16 +145,25 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
  **/
 struct mdev_driver {
 	const char *name;
-	int  (*probe)(struct device *dev);
-	void (*remove)(struct device *dev);
+	int (*probe)(struct mdev_device *dev);
+	void (*remove)(struct mdev_device *dev);
 	struct device_driver driver;
 };
 
 #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
 
-void *mdev_get_drvdata(struct mdev_device *mdev);
-void mdev_set_drvdata(struct mdev_device *mdev, void *data);
-const guid_t *mdev_uuid(struct mdev_device *mdev);
+static inline void *mdev_get_drvdata(struct mdev_device *mdev)
+{
+	return mdev->driver_data;
+}
+static inline void mdev_set_drvdata(struct mdev_device *mdev, void *data)
+{
+	mdev->driver_data = data;
+}
+static inline const guid_t *mdev_uuid(struct mdev_device *mdev)
+{
+	return &mdev->uuid;
+}
 
 extern struct bus_type mdev_bus_type;
 
@@ -146,7 +174,13 @@ int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
 void mdev_unregister_driver(struct mdev_driver *drv);
 
 struct device *mdev_parent_dev(struct mdev_device *mdev);
-struct device *mdev_dev(struct mdev_device *mdev);
-struct mdev_device *mdev_from_dev(struct device *dev);
+static inline struct device *mdev_dev(struct mdev_device *mdev)
+{
+	return &mdev->dev;
+}
+static inline struct mdev_device *mdev_from_dev(struct device *dev)
+{
+	return dev->bus == &mdev_bus_type ? to_mdev_device(dev) : NULL;
+}
 
 #endif /* MDEV_H */
-- 
cgit v1.2.3


From 91b9969d9c6bb7c02253bbfc536bfd892f636fdc Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 6 Apr 2021 16:40:27 -0300
Subject: vfio/mdev: Simplify driver registration

This is only done once, we don't need to generate code to initialize a
structure stored in the ELF .data segment. Fill in the three required
.driver members directly instead of copying data into them during
mdev_register_driver().

Further the to_mdev_driver() function doesn't belong in a public header,
just inline it into the two places that need it. Finally, we can now
clearly see that 'drv' derived from dev->driver cannot be NULL, firstly
because the driver core forbids it, and secondly because NULL won't pass
through the container_of(). Remove the dead code.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <4-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 Documentation/driver-api/vfio-mediated-device.rst |  5 +----
 drivers/vfio/mdev/mdev_driver.c                   | 15 +++++++--------
 drivers/vfio/mdev/vfio_mdev.c                     |  8 ++++++--
 include/linux/mdev.h                              |  6 +-----
 4 files changed, 15 insertions(+), 19 deletions(-)

(limited to 'include/linux/mdev.h')

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index c43c1dc33333..1779b85f014e 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -98,13 +98,11 @@ structure to represent a mediated device's driver::
 
      /*
       * struct mdev_driver [2] - Mediated device's driver
-      * @name: driver name
       * @probe: called when new device created
       * @remove: called when device removed
       * @driver: device driver structure
       */
      struct mdev_driver {
-	     const char *name;
 	     int  (*probe)  (struct mdev_device *dev);
 	     void (*remove) (struct mdev_device *dev);
 	     struct device_driver    driver;
@@ -115,8 +113,7 @@ to register and unregister itself with the core driver:
 
 * Register::
 
-    extern int  mdev_register_driver(struct mdev_driver *drv,
-				   struct module *owner);
+    extern int  mdev_register_driver(struct mdev_driver *drv);
 
 * Unregister::
 
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index 44c3ba7e56d9..041699571b7e 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -39,7 +39,8 @@ static void mdev_detach_iommu(struct mdev_device *mdev)
 
 static int mdev_probe(struct device *dev)
 {
-	struct mdev_driver *drv = to_mdev_driver(dev->driver);
+	struct mdev_driver *drv =
+		container_of(dev->driver, struct mdev_driver, driver);
 	struct mdev_device *mdev = to_mdev_device(dev);
 	int ret;
 
@@ -47,7 +48,7 @@ static int mdev_probe(struct device *dev)
 	if (ret)
 		return ret;
 
-	if (drv && drv->probe) {
+	if (drv->probe) {
 		ret = drv->probe(mdev);
 		if (ret)
 			mdev_detach_iommu(mdev);
@@ -58,10 +59,11 @@ static int mdev_probe(struct device *dev)
 
 static int mdev_remove(struct device *dev)
 {
-	struct mdev_driver *drv = to_mdev_driver(dev->driver);
+	struct mdev_driver *drv =
+		container_of(dev->driver, struct mdev_driver, driver);
 	struct mdev_device *mdev = to_mdev_device(dev);
 
-	if (drv && drv->remove)
+	if (drv->remove)
 		drv->remove(mdev);
 
 	mdev_detach_iommu(mdev);
@@ -79,16 +81,13 @@ EXPORT_SYMBOL_GPL(mdev_bus_type);
 /**
  * mdev_register_driver - register a new MDEV driver
  * @drv: the driver to register
- * @owner: module owner of driver to be registered
  *
  * Returns a negative value on error, otherwise 0.
  **/
-int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
+int mdev_register_driver(struct mdev_driver *drv)
 {
 	/* initialize common driver fields */
-	drv->driver.name = drv->name;
 	drv->driver.bus = &mdev_bus_type;
-	drv->driver.owner = owner;
 
 	/* register with core */
 	return driver_register(&drv->driver);
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index 91b7b8b9eb9c..cc9507ed85a1 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -152,14 +152,18 @@ static void vfio_mdev_remove(struct mdev_device *mdev)
 }
 
 static struct mdev_driver vfio_mdev_driver = {
-	.name	= "vfio_mdev",
+	.driver = {
+		.name = "vfio_mdev",
+		.owner = THIS_MODULE,
+		.mod_name = KBUILD_MODNAME,
+	},
 	.probe	= vfio_mdev_probe,
 	.remove	= vfio_mdev_remove,
 };
 
 static int __init vfio_mdev_init(void)
 {
-	return mdev_register_driver(&vfio_mdev_driver, THIS_MODULE);
+	return mdev_register_driver(&vfio_mdev_driver);
 }
 
 static void __exit vfio_mdev_exit(void)
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 52f7ea19dd0f..cb771c712da0 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -137,21 +137,17 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
 
 /**
  * struct mdev_driver - Mediated device driver
- * @name: driver name
  * @probe: called when new device created
  * @remove: called when device removed
  * @driver: device driver structure
  *
  **/
 struct mdev_driver {
-	const char *name;
 	int (*probe)(struct mdev_device *dev);
 	void (*remove)(struct mdev_device *dev);
 	struct device_driver driver;
 };
 
-#define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
-
 static inline void *mdev_get_drvdata(struct mdev_device *mdev)
 {
 	return mdev->driver_data;
@@ -170,7 +166,7 @@ extern struct bus_type mdev_bus_type;
 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
 void mdev_unregister_device(struct device *dev);
 
-int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
+int mdev_register_driver(struct mdev_driver *drv);
 void mdev_unregister_driver(struct mdev_driver *drv);
 
 struct device *mdev_parent_dev(struct mdev_device *mdev);
-- 
cgit v1.2.3


From 417fd5bf242d7691c15fe0bd705ab76c69276572 Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 6 Apr 2021 16:40:28 -0300
Subject: vfio/mdev: Use struct mdev_type in struct mdev_device

The kobj pointer in mdev_device is actually pointing at a struct
mdev_type. Use the proper type so things are understandable.

There are a number of places that are confused and passing both the mdev
and the mtype as function arguments, fix these to derive the mtype
directly from the mdev to remove the redundancy.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <5-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 drivers/vfio/mdev/mdev_core.c    | 16 ++++++----------
 drivers/vfio/mdev/mdev_private.h |  7 +++----
 drivers/vfio/mdev/mdev_sysfs.c   | 11 ++++++-----
 include/linux/mdev.h             |  4 +++-
 4 files changed, 18 insertions(+), 20 deletions(-)

(limited to 'include/linux/mdev.h')

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 057922a1707e..5ca0efa5266b 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -73,11 +73,9 @@ static void mdev_put_parent(struct mdev_parent *parent)
 static void mdev_device_remove_common(struct mdev_device *mdev)
 {
 	struct mdev_parent *parent;
-	struct mdev_type *type;
 	int ret;
 
-	type = to_mdev_type(mdev->type_kobj);
-	mdev_remove_sysfs_files(mdev, type);
+	mdev_remove_sysfs_files(mdev);
 	device_del(&mdev->dev);
 	parent = mdev->parent;
 	lockdep_assert_held(&parent->unreg_sem);
@@ -241,13 +239,11 @@ static void mdev_device_release(struct device *dev)
 	mdev_device_free(mdev);
 }
 
-int mdev_device_create(struct kobject *kobj,
-		       struct device *dev, const guid_t *uuid)
+int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
 {
 	int ret;
 	struct mdev_device *mdev, *tmp;
 	struct mdev_parent *parent;
-	struct mdev_type *type = to_mdev_type(kobj);
 
 	parent = mdev_get_parent(type->parent);
 	if (!parent)
@@ -285,14 +281,14 @@ int mdev_device_create(struct kobject *kobj,
 	}
 
 	device_initialize(&mdev->dev);
-	mdev->dev.parent  = dev;
+	mdev->dev.parent = parent->dev;
 	mdev->dev.bus     = &mdev_bus_type;
 	mdev->dev.release = mdev_device_release;
 	dev_set_name(&mdev->dev, "%pUl", uuid);
 	mdev->dev.groups = parent->ops->mdev_attr_groups;
-	mdev->type_kobj = kobj;
+	mdev->type = type;
 
-	ret = parent->ops->create(kobj, mdev);
+	ret = parent->ops->create(&type->kobj, mdev);
 	if (ret)
 		goto ops_create_fail;
 
@@ -300,7 +296,7 @@ int mdev_device_create(struct kobject *kobj,
 	if (ret)
 		goto add_fail;
 
-	ret = mdev_create_sysfs_files(mdev, type);
+	ret = mdev_create_sysfs_files(mdev);
 	if (ret)
 		goto sysfs_fail;
 
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 97e2225f7f49..f12e34e16ab9 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -40,11 +40,10 @@ struct mdev_type {
 int  parent_create_sysfs_files(struct mdev_parent *parent);
 void parent_remove_sysfs_files(struct mdev_parent *parent);
 
-int  mdev_create_sysfs_files(struct mdev_device *mdev, struct mdev_type *type);
-void mdev_remove_sysfs_files(struct mdev_device *mdev, struct mdev_type *type);
+int  mdev_create_sysfs_files(struct mdev_device *mdev);
+void mdev_remove_sysfs_files(struct mdev_device *mdev);
 
-int  mdev_device_create(struct kobject *kobj,
-			struct device *dev, const guid_t *uuid);
+int mdev_device_create(struct mdev_type *kobj, const guid_t *uuid);
 int  mdev_device_remove(struct mdev_device *dev);
 
 #endif /* MDEV_PRIVATE_H */
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index 18114f3e090a..bcfe48d56e8a 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -67,7 +67,7 @@ static ssize_t create_store(struct kobject *kobj, struct device *dev,
 	if (ret)
 		return ret;
 
-	ret = mdev_device_create(kobj, dev, &uuid);
+	ret = mdev_device_create(to_mdev_type(kobj), &uuid);
 	if (ret)
 		return ret;
 
@@ -249,8 +249,9 @@ static const struct attribute *mdev_device_attrs[] = {
 	NULL,
 };
 
-int mdev_create_sysfs_files(struct mdev_device *mdev, struct mdev_type *type)
+int mdev_create_sysfs_files(struct mdev_device *mdev)
 {
+	struct mdev_type *type = mdev->type;
 	struct kobject *kobj = &mdev->dev.kobj;
 	int ret;
 
@@ -271,15 +272,15 @@ int mdev_create_sysfs_files(struct mdev_device *mdev, struct mdev_type *type)
 create_files_failed:
 	sysfs_remove_link(kobj, "mdev_type");
 type_link_failed:
-	sysfs_remove_link(type->devices_kobj, dev_name(&mdev->dev));
+	sysfs_remove_link(mdev->type->devices_kobj, dev_name(&mdev->dev));
 	return ret;
 }
 
-void mdev_remove_sysfs_files(struct mdev_device *mdev, struct mdev_type *type)
+void mdev_remove_sysfs_files(struct mdev_device *mdev)
 {
 	struct kobject *kobj = &mdev->dev.kobj;
 
 	sysfs_remove_files(kobj, mdev_device_attrs);
 	sysfs_remove_link(kobj, "mdev_type");
-	sysfs_remove_link(type->devices_kobj, dev_name(&mdev->dev));
+	sysfs_remove_link(mdev->type->devices_kobj, dev_name(&mdev->dev));
 }
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index cb771c712da0..349e8ac1fe33 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -10,13 +10,15 @@
 #ifndef MDEV_H
 #define MDEV_H
 
+struct mdev_type;
+
 struct mdev_device {
 	struct device dev;
 	struct mdev_parent *parent;
 	guid_t uuid;
 	void *driver_data;
 	struct list_head next;
-	struct kobject *type_kobj;
+	struct mdev_type *type;
 	struct device *iommu_device;
 	bool active;
 };
-- 
cgit v1.2.3


From fbea43239074e16c91048f5ce70378664efbdb99 Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 6 Apr 2021 16:40:33 -0300
Subject: vfio/mdev: Remove duplicate storage of parent in mdev_device

mdev_device->type->parent is the same thing.

The struct mdev_device was relying on the kref on the mdev_parent to also
indirectly hold a kref on the mdev_type pointer. Now that the type holds a
kref on the parent we can directly kref the mdev_type and remove this
implicit relationship.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <10-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 drivers/vfio/mdev/mdev_core.c | 13 +++++--------
 drivers/vfio/mdev/vfio_mdev.c | 14 +++++++-------
 include/linux/mdev.h          |  1 -
 3 files changed, 12 insertions(+), 16 deletions(-)

(limited to 'include/linux/mdev.h')

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 4caedb3d4fbf..2a20bdaf6142 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -29,7 +29,7 @@ static DEFINE_MUTEX(mdev_list_lock);
 
 struct device *mdev_parent_dev(struct mdev_device *mdev)
 {
-	return mdev->parent->dev;
+	return mdev->type->parent->dev;
 }
 EXPORT_SYMBOL(mdev_parent_dev);
 
@@ -58,12 +58,11 @@ void mdev_release_parent(struct kref *kref)
 /* Caller must hold parent unreg_sem read or write lock */
 static void mdev_device_remove_common(struct mdev_device *mdev)
 {
-	struct mdev_parent *parent;
+	struct mdev_parent *parent = mdev->type->parent;
 	int ret;
 
 	mdev_remove_sysfs_files(mdev);
 	device_del(&mdev->dev);
-	parent = mdev->parent;
 	lockdep_assert_held(&parent->unreg_sem);
 	ret = parent->ops->remove(mdev);
 	if (ret)
@@ -212,7 +211,7 @@ static void mdev_device_release(struct device *dev)
 	struct mdev_device *mdev = to_mdev_device(dev);
 
 	/* Pairs with the get in mdev_device_create() */
-	mdev_put_parent(mdev->parent);
+	kobject_put(&mdev->type->kobj);
 
 	mutex_lock(&mdev_list_lock);
 	list_del(&mdev->next);
@@ -250,9 +249,8 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
 	mdev->dev.release = mdev_device_release;
 	mdev->dev.groups = parent->ops->mdev_attr_groups;
 	mdev->type = type;
-	mdev->parent = parent;
 	/* Pairs with the put in mdev_device_release() */
-	mdev_get_parent(parent);
+	kobject_get(&type->kobj);
 
 	guid_copy(&mdev->uuid, uuid);
 	list_add(&mdev->next, &mdev_list);
@@ -300,7 +298,7 @@ out_put_device:
 int mdev_device_remove(struct mdev_device *mdev)
 {
 	struct mdev_device *tmp;
-	struct mdev_parent *parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	mutex_lock(&mdev_list_lock);
 	list_for_each_entry(tmp, &mdev_list, next) {
@@ -321,7 +319,6 @@ int mdev_device_remove(struct mdev_device *mdev)
 	mdev->active = false;
 	mutex_unlock(&mdev_list_lock);
 
-	parent = mdev->parent;
 	/* Check if parent unregistration has started */
 	if (!down_read_trylock(&parent->unreg_sem))
 		return -ENODEV;
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index cc9507ed85a1..922729071c5a 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -24,7 +24,7 @@
 static int vfio_mdev_open(struct vfio_device *core_vdev)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	int ret;
 
@@ -44,7 +44,7 @@ static int vfio_mdev_open(struct vfio_device *core_vdev)
 static void vfio_mdev_release(struct vfio_device *core_vdev)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	if (likely(parent->ops->release))
 		parent->ops->release(mdev);
@@ -56,7 +56,7 @@ static long vfio_mdev_unlocked_ioctl(struct vfio_device *core_vdev,
 				     unsigned int cmd, unsigned long arg)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	if (unlikely(!parent->ops->ioctl))
 		return -EINVAL;
@@ -68,7 +68,7 @@ static ssize_t vfio_mdev_read(struct vfio_device *core_vdev, char __user *buf,
 			      size_t count, loff_t *ppos)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	if (unlikely(!parent->ops->read))
 		return -EINVAL;
@@ -81,7 +81,7 @@ static ssize_t vfio_mdev_write(struct vfio_device *core_vdev,
 			       loff_t *ppos)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	if (unlikely(!parent->ops->write))
 		return -EINVAL;
@@ -93,7 +93,7 @@ static int vfio_mdev_mmap(struct vfio_device *core_vdev,
 			  struct vm_area_struct *vma)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	if (unlikely(!parent->ops->mmap))
 		return -EINVAL;
@@ -104,7 +104,7 @@ static int vfio_mdev_mmap(struct vfio_device *core_vdev,
 static void vfio_mdev_request(struct vfio_device *core_vdev, unsigned int count)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->parent;
+	struct mdev_parent *parent = mdev->type->parent;
 
 	if (parent->ops->request)
 		parent->ops->request(mdev, count);
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 349e8ac1fe33..fb582adda28a 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -14,7 +14,6 @@ struct mdev_type;
 
 struct mdev_device {
 	struct device dev;
-	struct mdev_parent *parent;
 	guid_t uuid;
 	void *driver_data;
 	struct list_head next;
-- 
cgit v1.2.3


From 15fcc44be0c7afa2945b1896a96ac2ddf09f1fa7 Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 6 Apr 2021 16:40:34 -0300
Subject: vfio/mdev: Add mdev/mtype_get_type_group_id()

This returns the index in the supported_type_groups array that is
associated with the mdev_type attached to the struct mdev_device or its
containing struct kobject.

Each mdev_device can be spawned from exactly one mdev_type, which in turn
originates from exactly one supported_type_group.

Drivers are using weird string calculations to try and get back to this
index, providing a direct access to the index removes a bunch of wonky
driver code.

mdev_type->group can be deleted as the group is obtained using the
type_group_id.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <11-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 drivers/vfio/mdev/mdev_core.c    | 20 ++++++++++++++++++++
 drivers/vfio/mdev/mdev_private.h |  2 +-
 drivers/vfio/mdev/mdev_sysfs.c   | 15 +++++++++------
 include/linux/mdev.h             |  3 +++
 4 files changed, 33 insertions(+), 7 deletions(-)

(limited to 'include/linux/mdev.h')

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 2a20bdaf6142..5ae06f951a09 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -33,6 +33,26 @@ struct device *mdev_parent_dev(struct mdev_device *mdev)
 }
 EXPORT_SYMBOL(mdev_parent_dev);
 
+/*
+ * Return the index in supported_type_groups that this mdev_device was created
+ * from.
+ */
+unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
+{
+	return mdev->type->type_group_id;
+}
+EXPORT_SYMBOL(mdev_get_type_group_id);
+
+/*
+ * Used in mdev_type_attribute sysfs functions to return the index in the
+ * supported_type_groups that the sysfs is called from.
+ */
+unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj)
+{
+	return container_of(mtype_kobj, struct mdev_type, kobj)->type_group_id;
+}
+EXPORT_SYMBOL(mtype_get_type_group_id);
+
 /* Should be called holding parent_list_lock */
 static struct mdev_parent *__find_parent_device(struct device *dev)
 {
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index fddab240ccc3..6999c89db7b1 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -29,7 +29,7 @@ struct mdev_type {
 	struct kobject *devices_kobj;
 	struct mdev_parent *parent;
 	struct list_head next;
-	struct attribute_group *group;
+	unsigned int type_group_id;
 };
 
 #define to_mdev_type_attr(_attr)	\
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index 8c169d12ba7d..712fbc78b12e 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -92,9 +92,11 @@ static struct kobj_type mdev_type_ktype = {
 };
 
 static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
-						 struct attribute_group *group)
+						 unsigned int type_group_id)
 {
 	struct mdev_type *type;
+	struct attribute_group *group =
+		parent->ops->supported_type_groups[type_group_id];
 	int ret;
 
 	if (!group->name) {
@@ -110,6 +112,7 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
 	type->parent = parent;
 	/* Pairs with the put in mdev_type_release() */
 	mdev_get_parent(parent);
+	type->type_group_id = type_group_id;
 
 	ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
 				   "%s-%s", dev_driver_string(parent->dev),
@@ -135,8 +138,6 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
 		ret = -ENOMEM;
 		goto attrs_failed;
 	}
-
-	type->group = group;
 	return type;
 
 attrs_failed:
@@ -151,8 +152,11 @@ attr_create_failed:
 
 static void remove_mdev_supported_type(struct mdev_type *type)
 {
+	struct attribute_group *group =
+		type->parent->ops->supported_type_groups[type->type_group_id];
+
 	sysfs_remove_files(&type->kobj,
-			   (const struct attribute **)type->group->attrs);
+			   (const struct attribute **)group->attrs);
 	kobject_put(type->devices_kobj);
 	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
 	kobject_del(&type->kobj);
@@ -166,8 +170,7 @@ static int add_mdev_supported_type_groups(struct mdev_parent *parent)
 	for (i = 0; parent->ops->supported_type_groups[i]; i++) {
 		struct mdev_type *type;
 
-		type = add_mdev_supported_type(parent,
-					parent->ops->supported_type_groups[i]);
+		type = add_mdev_supported_type(parent, i);
 		if (IS_ERR(type)) {
 			struct mdev_type *ltype, *tmp;
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index fb582adda28a..41e919365223 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -46,6 +46,9 @@ static inline struct device *mdev_get_iommu_device(struct mdev_device *mdev)
 	return mdev->iommu_device;
 }
 
+unsigned int mdev_get_type_group_id(struct mdev_device *mdev);
+unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj);
+
 /**
  * struct mdev_parent_ops - Structure to be registered for each parent device to
  * register the device to mdev module.
-- 
cgit v1.2.3


From c2ef2f50ad0ccf5460bf4824bc6669240b6c7936 Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 6 Apr 2021 16:40:40 -0300
Subject: vfio/mdev: Remove kobj from mdev_parent_ops->create()

The kobj here is a type-erased version of mdev_type, which is already
stored in the struct mdev_device being passed in. It was only ever used to
compute the type_group_id, which is now extracted directly from the mdev.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <17-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c  | 2 +-
 drivers/s390/cio/vfio_ccw_ops.c   | 2 +-
 drivers/s390/crypto/vfio_ap_ops.c | 2 +-
 drivers/vfio/mdev/mdev_core.c     | 2 +-
 include/linux/mdev.h              | 3 +--
 samples/vfio-mdev/mbochs.c        | 2 +-
 samples/vfio-mdev/mdpy.c          | 2 +-
 samples/vfio-mdev/mtty.c          | 2 +-
 8 files changed, 8 insertions(+), 9 deletions(-)

(limited to 'include/linux/mdev.h')

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 16e1e4a38aa1..6bf176e8426e 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -689,7 +689,7 @@ static void kvmgt_put_vfio_device(void *vgpu)
 	vfio_device_put(vdev->vfio_device);
 }
 
-static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
+static int intel_vgpu_create(struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = NULL;
 	struct intel_vgpu_type *type;
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 767ac41686fe..10407cf67583 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -110,7 +110,7 @@ static struct attribute_group *mdev_type_groups[] = {
 	NULL,
 };
 
-static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
+static int vfio_ccw_mdev_create(struct mdev_device *mdev)
 {
 	struct vfio_ccw_private *private =
 		dev_get_drvdata(mdev_parent_dev(mdev));
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 1ffdd411201c..d319152dd484 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -322,7 +322,7 @@ static void vfio_ap_matrix_init(struct ap_config_info *info,
 	matrix->adm_max = info->apxa ? info->Nd : 15;
 }
 
-static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
+static int vfio_ap_mdev_create(struct mdev_device *mdev)
 {
 	struct ap_matrix_mdev *matrix_mdev;
 
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 5ae06f951a09..10eff33ce1f2 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -286,7 +286,7 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
 		goto out_put_device;
 	}
 
-	ret = parent->ops->create(&type->kobj, mdev);
+	ret = parent->ops->create(mdev);
 	if (ret)
 		goto out_unlock;
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 41e919365223..c3a800051d61 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -61,7 +61,6 @@ unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj);
  * @create:		Called to allocate basic resources in parent device's
  *			driver for a particular mediated device. It is
  *			mandatory to provide create ops.
- *			@kobj: kobject of type for which 'create' is called.
  *			@mdev: mdev_device structure on of mediated device
  *			      that is being created
  *			Returns integer: success (0) or error (< 0)
@@ -107,7 +106,7 @@ struct mdev_parent_ops {
 	const struct attribute_group **mdev_attr_groups;
 	struct attribute_group **supported_type_groups;
 
-	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
+	int     (*create)(struct mdev_device *mdev);
 	int     (*remove)(struct mdev_device *mdev);
 	int     (*open)(struct mdev_device *mdev);
 	void    (*release)(struct mdev_device *mdev);
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index a1af30df10a2..ac4d0dc24907 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -506,7 +506,7 @@ static int mbochs_reset(struct mdev_device *mdev)
 	return 0;
 }
 
-static int mbochs_create(struct kobject *kobj, struct mdev_device *mdev)
+static int mbochs_create(struct mdev_device *mdev)
 {
 	const struct mbochs_type *type =
 		&mbochs_types[mdev_get_type_group_id(mdev)];
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index 08c15f9f06a8..da88fd7dd423 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -216,7 +216,7 @@ static int mdpy_reset(struct mdev_device *mdev)
 	return 0;
 }
 
-static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)
+static int mdpy_create(struct mdev_device *mdev)
 {
 	const struct mdpy_type *type =
 		&mdpy_types[mdev_get_type_group_id(mdev)];
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 191a587a8d5a..f2e36c06ac6a 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -708,7 +708,7 @@ accessfailed:
 	return ret;
 }
 
-static int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
+static int mtty_create(struct mdev_device *mdev)
 {
 	struct mdev_state *mdev_state;
 	int nr_ports = mdev_get_type_group_id(mdev) + 1;
-- 
cgit v1.2.3


From 9169cff168ff262b4b78597f542e23843d0c494a Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 6 Apr 2021 16:40:41 -0300
Subject: vfio/mdev: Correct the function signatures for the
 mdev_type_attributes

The driver core standard is to pass in the properly typed object, the
properly typed attribute and the buffer data. It stems from the root
kobject method:

  ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,..)

Each subclass of kobject should provide their own function with the same
signature but more specific types, eg struct device uses:

  ssize_t (*show)(struct device *dev, struct device_attribute *attr,..)

In this case the existing signature is:

  ssize_t (*show)(struct kobject *kobj, struct device *dev,..)

Where kobj is a 'struct mdev_type *' and dev is 'mdev_type->parent->dev'.

Change the mdev_type related sysfs attribute functions to:

  ssize_t (*show)(struct mdev_type *mtype, struct mdev_type_attribute *attr,..)

In order to restore type safety and match the driver core standard

There are no current users of 'attr', but if it is ever needed it would be
hard to add in retroactively, so do it now.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <18-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 drivers/gpu/drm/i915/gvt/gvt.c    | 21 +++++++++++----------
 drivers/s390/cio/vfio_ccw_ops.c   | 15 +++++++++------
 drivers/s390/crypto/vfio_ap_ops.c | 12 +++++++-----
 drivers/vfio/mdev/mdev_core.c     | 14 ++++++++++++--
 drivers/vfio/mdev/mdev_sysfs.c    | 11 ++++++-----
 include/linux/mdev.h              | 11 +++++++----
 samples/vfio-mdev/mbochs.c        | 26 +++++++++++++++-----------
 samples/vfio-mdev/mdpy.c          | 24 ++++++++++++++----------
 samples/vfio-mdev/mtty.c          | 18 +++++++++---------
 9 files changed, 90 insertions(+), 62 deletions(-)

(limited to 'include/linux/mdev.h')

diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
index 4b47a18e9dfa..3703814a669b 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.c
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -54,14 +54,15 @@ intel_gvt_find_vgpu_type(struct intel_gvt *gvt, unsigned int type_group_id)
 	return &gvt->types[type_group_id];
 }
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	struct intel_vgpu_type *type;
 	unsigned int num = 0;
-	void *gvt = kdev_to_i915(dev)->gvt;
+	void *gvt = kdev_to_i915(mtype_get_parent_dev(mtype))->gvt;
 
-	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(kobj));
+	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(mtype));
 	if (!type)
 		num = 0;
 	else
@@ -70,19 +71,19 @@ static ssize_t available_instances_show(struct kobject *kobj,
 	return sprintf(buf, "%u\n", num);
 }
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-		char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }
 
-static ssize_t description_show(struct kobject *kobj, struct device *dev,
-		char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	struct intel_vgpu_type *type;
-	void *gvt = kdev_to_i915(dev)->gvt;
+	void *gvt = kdev_to_i915(mtype_get_parent_dev(mtype))->gvt;
 
-	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(kobj));
+	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(mtype));
 	if (!type)
 		return 0;
 
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 10407cf67583..491a64c61fff 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -71,23 +71,26 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
 	return NOTIFY_DONE;
 }
 
-static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "I/O subchannel (Non-QDIO)\n");
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_CCW_STRING);
 }
 static MDEV_TYPE_ATTR_RO(device_api);
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
-	struct vfio_ccw_private *private = dev_get_drvdata(dev);
+	struct vfio_ccw_private *private =
+		dev_get_drvdata(mtype_get_parent_dev(mtype));
 
 	return sprintf(buf, "%d\n", atomic_read(&private->avail));
 }
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index d319152dd484..0ce00c9311d3 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -366,15 +366,17 @@ static int vfio_ap_mdev_remove(struct mdev_device *mdev)
 	return 0;
 }
 
-static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT);
 }
 
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	return sprintf(buf, "%d\n",
 		       atomic_read(&matrix_dev->available_instances));
@@ -382,8 +384,8 @@ static ssize_t available_instances_show(struct kobject *kobj,
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_AP_STRING);
 }
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 10eff33ce1f2..2a85d6fcb7dd 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -47,12 +47,22 @@ EXPORT_SYMBOL(mdev_get_type_group_id);
  * Used in mdev_type_attribute sysfs functions to return the index in the
  * supported_type_groups that the sysfs is called from.
  */
-unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj)
+unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
 {
-	return container_of(mtype_kobj, struct mdev_type, kobj)->type_group_id;
+	return mtype->type_group_id;
 }
 EXPORT_SYMBOL(mtype_get_type_group_id);
 
+/*
+ * Used in mdev_type_attribute sysfs functions to return the parent struct
+ * device
+ */
+struct device *mtype_get_parent_dev(struct mdev_type *mtype)
+{
+	return mtype->parent->dev;
+}
+EXPORT_SYMBOL(mtype_get_parent_dev);
+
 /* Should be called holding parent_list_lock */
 static struct mdev_parent *__find_parent_device(struct device *dev)
 {
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index 712fbc78b12e..f5cf1931c54e 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -26,7 +26,7 @@ static ssize_t mdev_type_attr_show(struct kobject *kobj,
 	ssize_t ret = -EIO;
 
 	if (attr->show)
-		ret = attr->show(kobj, type->parent->dev, buf);
+		ret = attr->show(type, attr, buf);
 	return ret;
 }
 
@@ -39,7 +39,7 @@ static ssize_t mdev_type_attr_store(struct kobject *kobj,
 	ssize_t ret = -EIO;
 
 	if (attr->store)
-		ret = attr->store(&type->kobj, type->parent->dev, buf, count);
+		ret = attr->store(type, attr, buf, count);
 	return ret;
 }
 
@@ -48,8 +48,9 @@ static const struct sysfs_ops mdev_type_sysfs_ops = {
 	.store = mdev_type_attr_store,
 };
 
-static ssize_t create_store(struct kobject *kobj, struct device *dev,
-			    const char *buf, size_t count)
+static ssize_t create_store(struct mdev_type *mtype,
+			    struct mdev_type_attribute *attr, const char *buf,
+			    size_t count)
 {
 	char *str;
 	guid_t uuid;
@@ -67,7 +68,7 @@ static ssize_t create_store(struct kobject *kobj, struct device *dev,
 	if (ret)
 		return ret;
 
-	ret = mdev_device_create(to_mdev_type(kobj), &uuid);
+	ret = mdev_device_create(mtype, &uuid);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index c3a800051d61..1fb34ea394ad 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -47,7 +47,8 @@ static inline struct device *mdev_get_iommu_device(struct mdev_device *mdev)
 }
 
 unsigned int mdev_get_type_group_id(struct mdev_device *mdev);
-unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj);
+unsigned int mtype_get_type_group_id(struct mdev_type *mtype);
+struct device *mtype_get_parent_dev(struct mdev_type *mtype);
 
 /**
  * struct mdev_parent_ops - Structure to be registered for each parent device to
@@ -123,9 +124,11 @@ struct mdev_parent_ops {
 /* interface for exporting mdev supported type attributes */
 struct mdev_type_attribute {
 	struct attribute attr;
-	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
-	ssize_t (*store)(struct kobject *kobj, struct device *dev,
-			 const char *buf, size_t count);
+	ssize_t (*show)(struct mdev_type *mtype,
+			struct mdev_type_attribute *attr, char *buf);
+	ssize_t (*store)(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, const char *buf,
+			 size_t count);
 };
 
 #define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index ac4d0dc24907..861c76914e76 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1330,37 +1330,41 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n", kobj->name);
+	const struct mbochs_type *type =
+		&mbochs_types[mtype_get_type_group_id(mtype)];
+
+	return sprintf(buf, "%s\n", type->name);
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-description_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(kobj)];
+		&mbochs_types[mtype_get_type_group_id(mtype)];
 
 	return sprintf(buf, "virtual display, %d MB video memory\n",
 		       type ? type->mbytes  : 0);
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(kobj)];
+		&mbochs_types[mtype_get_type_group_id(mtype)];
 	int count = (max_mbytes - mbochs_used_mbytes) / type->mbytes;
 
 	return sprintf(buf, "%d\n", count);
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index da88fd7dd423..885b88ea20e2 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -652,18 +652,21 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n", kobj->name);
+	const struct mdpy_type *type =
+		&mdpy_types[mtype_get_type_group_id(mtype)];
+
+	return sprintf(buf, "%s\n", type->name);
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-description_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	const struct mdpy_type *type =
-		&mdpy_types[mtype_get_type_group_id(kobj)];
+		&mdpy_types[mtype_get_type_group_id(mtype)];
 
 	return sprintf(buf, "virtual display, %dx%d framebuffer\n",
 		       type ? type->width  : 0,
@@ -671,15 +674,16 @@ description_show(struct kobject *kobj, struct device *dev, char *buf)
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	return sprintf(buf, "%d\n", max_devices - mdpy_count);
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index f2e36c06ac6a..b9b24be4abda 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1292,23 +1292,24 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	static const char *name_str[2] = { "Single port serial",
 					   "Dual port serial" };
 
 	return sysfs_emit(buf, "%s\n",
-			  name_str[mtype_get_type_group_id(kobj)]);
+			  name_str[mtype_get_type_group_id(mtype)]);
 }
 
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	struct mdev_state *mds;
-	unsigned int ports = mtype_get_type_group_id(kobj) + 1;
+	unsigned int ports = mtype_get_type_group_id(mtype) + 1;
 	int used = 0;
 
 	list_for_each_entry(mds, &mdev_devices_list, next)
@@ -1319,9 +1320,8 @@ available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }
-- 
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